In recent years, Liquid Crystal Display (LCD), Organic Light Emitting Diode (OLED) and other panel display devices have been gradually replaced the CRT displays and become the major production in the display device market. The OLED possesses many outstanding properties of self-illumination, low driving voltage, high luminescence efficiency, fast response, high clarity and contrast, near 180° view angle, wide range of working temperature, applicability of flexible display and large scale full color display. The OLED is recognized as the most potential flat panel display by industry.
The OLED display device generally comprises a substrate, an anode located on the substrate, a Hole Injection Layer located on the anode, a Hole Transporting Layer located on the Hole Injection Layer, an emitting layer located on the Hole Transporting Layer, an Electron Transport Layer located on the emitting layer, an Electron Injection Layer located on the Electron Transport Layer and a Cathode located on the Electron Injection Layer. The principle of the OLED is that the illumination generates due to the carrier injection and recombination under the electric field driving of the semiconductor material and the organic semiconductor illuminating material. Specifically, the ITO transparent electrode and the metal electrode are respectively employed as the anode and the cathode of the Display. Under certain voltage driving, the Electron and the Hole are respectively injected into the Electron and Hole Transporting Layers from the cathode and the anode. The Electron and the Hole respectively migrate from the Electron and Hole Transporting Layers to the Emitting layer and bump into each other in the Emitting layer to form an exciton to excite the emitting molecule. The latter can illuminate after the radiative relaxation.
In recent years, the spaces between the pixels gradually get smaller with the higher resolution of the displays and the pixels per inch (ppi) increase of the pixels. Meanwhile, with the efficiency of the luminescent material of the OLED display device is raised, the high brightness with low current and low voltage can be realized to reduce the power consumption, accordingly. However, just due to the high efficiency of the luminescent material of the OLED display device, which can light with a small current conducted, a tiny current leaked from one pixel to another adjacent pixel can cause the aforesaid high efficient luminescent material to light, the adjacent pixel which should not light may emit light often. The emitting light due to the leakage current is so called the leaking emitting light. The color mixture will occur and change the color coordinates if the leaking emitting light happened. Besides, as the leaking emitting light due to the leakage current happens in the low brightness area, the black brightness will increase.
Aiming at this problem, the leaking emitting light can be inhibited by reducing the efficiency of the luminescent material and degrading the resolution of the display device. Nevertheless, with the constantly increasing demands for the productions of the low power consumption and high resolution from the users, the leaking emitting light problem has to be solved under circumstance that the efficiency of the luminescent material is not reduced and the resolution of the display device is not degraded.